From Twitter https://twitter.com/: Born OTD 1776, Amedeo Avogadro proposed equal volumes of gases at same T and P contain equal numbers of molecules http://physicstoday.scitation.org/action/cookieAbsent https://twitter.com/PhysicsToday/status/895275585060188160/photo/1 https://chirp.cooleysekula.net/attachment/38498